oh, dope: banksy sneaks his artwork into 4 new york museums. in trenchcoat and glasses no less. (see the whole deal at wooster.)
i pulled a similar prank once. the kroeber art building was hosting an honors thesis show. i printed out my name on a slip of paper and tagged it next to the air-con control switch (the switches looked lonely in the corner, so i named them "disenchanted doves") and watched a few art kids/teachers muse at it in wonder.